1. Field of the Invention
The present invention relates to a method of manufacturing an improved golf club head and the improved golf club head thus manufactured.
2. Description of Background and Relevant Information
In the sport of golf, the player propels his or her ball by striking it with a golf club which is constituted by a handle or shaft, which comprises a head at its lower end, whereas its upper end is equipped with a handgrip or grip.
In order to play golf, the player has a certain number of clubs, all of which are different with respect to one another and which generally fall under three categories, viz., woods, irons and putters.
At this time, the clubs used by golfers from the tee at the start of a hole, i.e., the club used for carrying the ball over long distances, are "woods". Each manufacturer gives his products, including the woods in a line of golf clubs, a specific structure, while complying with a certain number of rules that are necessary to standardize such golf clubs in competitions. As such, certain dimensions, inclinations and masses are regulated, whereas a large number of other parameters are completely unregulated, resulting in a large diversity in products having different designs. While playing, players use other clubs, i.e., "irons", that are subject to the same types of rules.
The precision of a golf shot depends upon a certain number of parameters, particularly human parameters, but also parameters connected to the construction of the club itself, and especially the distribution of mass and the club structure. Movement of the club before striking the ball can be more or less precise and the position of the golf club head during impact can be more or less good with respect to the ball. Golfers are very well aware of the fact that the smallest imprecision at the moment of striking the ball will have significant consequences. In fact, at the moment of impact, the point of impact of the ball on the striking surface of the club head should be perfectly perpendicular, joining the center of gravity of the ball and the center of gravity of the golf club head. If this condition is not adhered to during impact, the club head, under the effect of the impact, will pivot and the striking surface will open or close and the path of the ball will not be the one desired. If the striking surface opens substantially, the ball will go to the right and if the striking surface closes, the ball will go the left. Current club heads demonstrate very little tolerance in this regard and it becomes necessary to hit the ball with a great deal of precision.
Golf clubs used on the tee or otherwise for great distances typically comprise a metallic head, have a fine thickness, are hollow and are constituted by the assembly of several metal elements welded to one another and defining an inner closed cavity. Such constructions, described in U.S. Pat. Nos. 4,438,931 and 5,024,437 and Japanese Patent Publication No. 61-33973, are such that the clubs thus constructed have a tolerance that cannot be improved beyond a certain threshold due to the critical mass of the head and due to the isotropic nature of the material. In fact, no addition of weights is generally possible without exceeding the mass limits beyond which the club can no longer be balanced correctly and the distribution of mass is closely linked to the shape of the head itself. Another disadvantage of this type of head is related to the nature of the material of the impact surface which, although it allows a direct transmission of information to the player, also conversely gives rise to disagreeable sound and sensation at impact.
For some years now, heads made entirely of a composite material, with the exception of the sole, have been manufactured. Such types of constructions are rarely favored by professional players, because they are, most often, made of a single element, by the compression molding method, without any particular regard to the distribution of mass. In addition, such constructions do not offer a positive sensation to the player at impact due to the substantial graphite thickness of the front wall, which is necessary to ensure resistance.
A head made of a plastic material is disclosed in British Patent Publication No. 2,128,539. This head is made of a single thermoplastic element injected into a mold around a meltable core. The head thus manufactured does not allow a good control over the trajectory of the balls because the problem of balancing the club is not resolved.
U.S. Pat. No. 5,000,454 discloses a head made of a reinforced plastic material and comprises an element acting both as the reinforcement of the striking face and as the balancing weight. However, such a structure does not yet permit the club to be balanced satisfactorily.